A conventional noncontact power supply device includes a power transmission device that transmits power by a magnetic flux, and a power reception device that receives the magnetic flux which is output from the power transmission device. The power transmission device includes a power-transmission resonant circuit, and a plurality of switching elements. The power-transmission resonant circuit outputs an alternating magnetic flux to the power reception device by alternating power supplied from a power source circuit. The plurality of switching elements perform a switching operation for making the power-transmission resonant circuit generate the alternating magnetic flux. The power reception device includes a power receiving coil and a rectifier circuit. The power receiving coil is magnetically coupled to the power-transmission resonant circuit. The rectifier circuit supplies the power output from the power receiving coil to a load.
In this case, it is generally known that when a drive frequency of each switching element, a resonance frequency of the power-transmission resonant circuit, and a resonance frequency of the power receiving coil are substantially coincided with each other, power transmission efficiency from the power transmission device to the power reception device improves. Therefore, there is disclosed a noncontact power supply device in which a power transmission device and a power reception device are designed such that the above relationship is established (for example, refer to PTL 1).
However, values of elements configuring a circuit of the noncontact power supply device vary at a manufacturing time. Therefore, at least one of the drive frequency and each resonance frequency is deviated from a design value in some cases. Accordingly, in manufacturing a noncontact power supply device having high transmission efficiency by preventing a deviation from a design value of each element, there is a concern about reduction in productivity. On the other hand, power transmission efficiency is one of main factors required for the noncontact power supply device. Therefore, it is not preferable to sacrifice power transmission efficiency as a result of prioritizing the productivity.